Increase of forest carbon sequestration is widely accepted as an important strategy for mitigating climate change. Based on rural households'and national state forest farms'survey data collected in the provinces of Zhejiang, Fujian and Jiangxi, Faustmann model was applied to analyze the optimal rotation age and forest land expectation value between traditional timber management and combined timber and carbon management for Chinese fir in this study. It compared the carbon supply potential capacity difference of forest management subjects, and sensitivity analysis was also conducted with different interest rate and management cost to simulate the influence on the carbon supply. It was found that the optimal rotation of Chinese fir in the joint management for households and national state forest farms has not changed due to the fact that timber price is much higher than carbon price, suggesting that optimal decision for Chinese fir management will not change significantly and carbon sequestration supply for current forest land would not change within a large range change of carbon price. The object of carbon benefit and traditional management can be coordinated. National state forest farms is much more suitable for carbon supply due to the advantage of management scale, technologies and capital. The potential invest value of carbon forest is much more higher in the low interest rate, and higher management cost can make higher carbon supply.
Eco-risk assessment is a hotspot arising in recent 20 years, due to the spatial heterogeneity and the complexity in assessment, as well as an integrated junction for geography, ecology, and environment risk evaluation. The study of ecological risk is helpful for understanding local ecological environment, reducing ecological risk, and finally improving the interactions between human beings and nature. To reveal the impact of ecological risk of oasis change in the small watershed of the Shiyang River Basin, Wuwei and Minqin oases were chosen as the study area. Landscape information was obtained from satellite remote sensing TM images of 1987, 2000 and 2010. The grid by 4 km×4 km was created as the auxiliary evaluation unit, and the GIS technology was employed as the data integration analysis platform. In order to generate the map of oasis eco-risk in 1987, 2000 and 2010, the spatial overlay method was used to make the index a spatial variable. Besides, the landscape interference index, fragile landscape degree, landscape dominance index and fragmentation index were used to analyze the relationship between landscape pattern and the eco- risk degree through the supporting of ArcGIS 10.0, ArcView 3.2 and FRAGSTATS softwares. Besides, based on the overlay analysis of every netfish of the landscape index, the eco-risk degree was reflected by spatial expression. Meanwhile, the spatial statistic method was also used to analyze the spatio-temporal process of landscape structures and ecological risk. The results showed that: 1) the urban and rural land expanded rapidly from 1987 to 2010. At the same time, the farmland and grassland decreased at a large scale, and the preponderant landscape changed from farmland and grassland to farmland and construction land. 2) The Wuwei oasis ecological risk has experienced the transition from high to moderate change, and the ecological risk as a whole tended to be better while the Minqin oasis eco-risk turned from medium /higher- risk to higher- risk/highest- risk. The ecological risk of the whole study area was deteriorated in the past 20 years. 3) The Wuwei oasis elements mainly tended to cluster and its value was higher than the average. It showed the low eco- risk area was much more clustered, and the trend was increasing. Comparatively, the elements of Minqin oasis that were lower than the average tended to be clustered, the high eco-risk area clustered extremely. It also showed that the cluster characteristics increased in area and expanded in space. Therefore, Wuwei oasis should expand the scale of the facilities of agriculture or high-efficiency water saving. At the same time, the ecological key factors such as forest for conservation of water supply and alpine grassland should be protected. What's more, desertification governance in Minqin oasis is particularly important. Through the grass square, cotton stem, corn straw, drought-tolerant plants can effectively manage desertification, and improve the resistance of eco-environmental change.
There are a certain degree of low-efficient Pinus massoniana plantations in a hilly area of the upper reaches of the Yangtze River. To understand the forest gap formed by artificial tending thinning to regulate forest structure and the impact on ecological effect of low-efficient plantation, which to provide critical scientific basis for the optimum control mode of forest gap size of masson pine plantation in the hilly area. The study takes seven gaps with different sizes (G1: 100 m2, G2: 225 m2, G3: 400 m2, G4: 625 m2, G5: 900 m2, G6: 1225 m2, G7: 1600 m2) as objects and pure 39-year-old plantation as a control, analyzes the seasonal variations of soil microbial biomass carbon (MBC), microbial biomass nitrogen (MBN) and microbial biomass phosphorus (MBP) at the centers and edges of the gaps. The results show that: 1) the gap size has significant effect on soil MBC and MBP at different locations, but has no significant impact on the soil MBN. MBN and MBC vary with the same trend, both showing unimodal type change with the increase of gaps, but MBN changes in a smaller range. MBP has only a single peak variation at the gap center. The soil MBC, MBN and MBP are respectivly higher in gaps with area of 400-900 m2, 225-625 m2 and 625-900 m2. 2) Seasonal changes have significantly influence on soil MBC, MBN and MBP. MBC is higher in summer and lower in spring. MBN is higher in summer and lower in winter. MBP changes in more complicated way, and it is relatively high in autumn. Among them, the MBC in 100-900 m2 gaps is significantly higher in summer than in spring by an increase of more than twice. 3) MBC, MBN and MBP at the center and the edge of the gaps are not significantly different, but the soil MBC and MBN in the forest gaps are significantly higher than those at the understory. 4) Soil temperature has significant influence on MBC and MBN, while soil moisture has significant influence on MBN and MBP. Our findings support that medium-sized gaps are more conducive to microbial biomass appreciation. Compared with pure pine forest, soil microbial activity in the gaps improves greatly. Soil temperature and moisture are important environmental factors affecting soil microbial biomass of Pinus massoniana plantations after gap's formation. The above results provide certain scientific basis to rebuild low-efficient plantation and deeply understand the belowground ecological process.
According to the gridded Chinese ground precipitation dataset with a resolution of 0.5°× 0.5° released by National Meteorological Information Center, extreme precipitation indices including maximum 1- day precipitation (RX1day), maximum 5-day precipitation (RX5day), very wet day precipitation (R95), wet day precipitation (PRCPTOT), consecutive dry days (CDD) and simple daily intensity index (SDII) in arid areas in Northwest China during 1961-2011 is analyzed using Sen's slope, correlation analysis and other methods. The connection between each extreme precipitation index and the Arctic oscillation is discussed, and the gridded indices in this study are compared with those in previous research using observation data. The result indicates that most indices show a slightly increasing trend, except CDD with statistically significant decrease (P<0.01). Spatially, RX1day, RX5day, R95, PRCPTOT and SDII have significantly increased in the western part and slightly decreased in the east part, and CDD generally presents a decreasing trend. The higher correlation (P<0.05) exists between NCAR-based summer Arctic oscillations index and CDD, which indicates a relation between Arctic oscillation in summer and drought events in the study area. Compared with the previous research using observation data, the gridded data have greater spatial coverage, which is good at describing detailed spatial variation, especially in the mountainous regions like the Tianshan Mountains and Altai Mountains.
Based on the daily weather data of 50 meteorological observation stations from 1960 to 2009 in the middle reach of the Yangtze River, the change characteristics of agricultural climate resources including heat, light and precipitation of temperature-defined growth season, early-season rice growth season and late-season rice growth season during 1960-2009, 1960-1984 and 1985-2009 were analyzed respectively, and its possible influences on double-season rice production were discussed in this paper. From 1960 to 2009 in the middle reach of the Yangtze River, the climatic tendency of mean daily temperature, mean daily minimum temperature, mean daily maximal temperature, active accumulated temperature ≥10 ℃, sunshine hours and precipitation were 0.08 ℃/10 a, 0.09 ℃/10 a, 0.07 ℃/10 a, 66.3 ℃/10 a, -31.7 h/10 a and 3.7 mm/10 a respectively during temperature-defined growth season. So the change characteristics of agricultural climate resources in this region were temperature increasing, accumulated temperature adding, temperature-defined growth season prolonging, sunshine hours decreasing and slight precipitation increasing. So increasing temperature and adding accumulated temperature were likely to accelerate crop development, shorten crop growth duration, and aggravate crop disease and pest, at the same time, the decreasing sunshine hours might affect leaf photosynthesis and yield. The climatic tendency of mean daily temperature, and active accumulated temperature ≥10 ℃ were 0.20 ℃/10 a and 48.9 ℃/10 a during early-season rice growth season, and 0.09 ℃/10 a and 14.6 ℃/10 a during late-season rice growth season. The climatic tendency of sunshine hours was -18.6 h/10 a during early- season rice growth season, -42.7 h/10 a during late-season rice growth season, while precipitation was 1.9 mm/10 a during early-season rice growth season, 8.7 mm/10 a during late-season rice growth season. So the tendency of temperature increasing during early-season rice growth season was more than that during late-season rice growth season, but the tendency of precipitation increasing, sunshine hours decreasing during late-season rice growth season were more than those during early-season rice growth season. Therefore, obvious temperature increase and accumulated temperature addition during early-season rice growth season might be advantageous to advance sowing date, select variety with relatively long growth duration,improve the yield potential and yield for early-season rice. But unobvious temperature increase and obvious sunshine hours decline during late-season rice growth season might be disadvantageous to photosynthetic enhancement, yield formation, and affect yield potential and yield improvement for late-season rice production. Heat, light and precipitation were increasing synchronously in some regions such as Jianghan Plain and Dongting Lake Plain which had good basic condition for rice production. In other regions, the change of agricultural climate resources was asynchronous, the heat and precipitation was increasing, but the sunshine hours was decreasing. Furthermore, the advantage of good basic condition and predominant climatic resource could be utilized to develop sweeping rice production with high efficiency, and to enhance rice production potential.
Geostatistics combined with classic statistics was applied to analyze the spatial variability and reasonable sampling number of soil organic carbon at county scale in the gully and plain regions of the Loess Plateau. The results showed that: 1) The coefficient of variation was relatively small in the gully region, ranging from 0.176 to 0.200. The plain presented a larger coefficient of variation, ranging from 0.24 to 0.26. 2) Classic statistical analyses showed reasonable sampling number was 64 in the gully region and 110 in the plain region by the 5% accuracy and 95% confidence interval. 3) The two regions both presented strong spatial dependence and small range, being 2250 m and 900 m respectively. In Zhuanglang County, the SOC contents in the north were higher than those in the south, the SOC contents in the west were higher than those in the east part, and some high values were in patch forms. In Wugong County, the SOC contents in the southwestern and central parts were high, and the high values were more concentrative. Based on the spatial correlation of SOC and validation,we concluded that reasonable sampling number of SOC was about 903 and 1838 in the gully and plain region respectively. The study was important to reasonably evaluate the prediction accuracy about soil organic carbon storage in the Loess Plateau region.
Water is scarce in China. Although the total water amount is 23256.7 × 108 m3 in 2011, yet along with the increasing population, the per capita water resource is only 2093 m3. The low level of the water quantity would restrict the development of economy and society. The green and sustainable development means a new area to combine green economic with sustainable development. Therefore the water resource is the foundation of the Green and Sustainable development in China. This article studied the changes in China water footprint and its intensity during 1997-2007. Through the changes we analyzed the driving factors, and put forward some forecast for the water saving policy. This research was based on an economic method, Input-Output analysis method. The results show that: the total water footprint intensity declined by 9.1% (average annual rate of descent). However, the total water footprint was increased; the average annual growth rate is 14.2%. The proportion of total output virtual water footprint to the total water footprint was 12.0%, 14.6% and 22.5% in China in 1997, 2002 and 2007, higher than the total input. There are three factors made the total water footprint intensity declined, i.e., the development of water-saving technology, the implementation of water-saving policies and the trade links among industries. However the greatly improved economy, affected by macro-control policies, makes the water footprint increase. Combined with the total water footprint intensity, the results show that it is the unreasonable trading structure and expansive trading scale that lead to the water export in China and brings negative effects on water saving. Finally, there are five prior ways to establish new water saving policies: Explore the new way for the water saving technology (such as improving the prolificacy of water per consumption); resolve the difficult water saving problem by the sectoral connection and trading links; complete the water saving measures of developing sectors; adjust the import-export trading structure and implement the virtual water strategy at regional level.
As a kind of clean, efficient and high-quality unconventional natural gas resources, exploration and development of shale gas can effectively enhance the proportion of natural gas in China's primary energy consumption structure, to improve energy structure and ensure energy security. In this paper, we took the feasibility evaluation as a starting point. An evaluation index system consisting of 19 indicators in terms of the resources and occurrence conditions, comprehensive exploitation and utilization conditions, environmental safety and market prospects influencing exploitation suitability of shale gas has been established based on comprehensive consideration of China shale gas development. Making Sino-US comparison study, we explored the suitability issues on China's recent large-scale exploitation and utilization of shale gas. The main conclusions are as follows: Firstly, some indicators such as market demand, cost and price, core technical conditions,gas content, water pollution,etc., are key factors affecting the development of shale gas. Secondly, comparison score results show the feasibility of development of shale gas in the two countries respectively belongs to moderate downward range and moderate upward range, with a great scoring gap being respectively 0.49971 points and 0.74159 points. Thirdly, great scoring gap between the two countries is mainly due to the huge difference in resources and occurrence conditions, comprehensive exploitation and utilization conditions. From the present shale gas development situation in China and the United States, the results coincide with reality to a higher degree.
Agricultural agglomeration has become the effective spatial organization form for agricultural division. In this paper, animal husbandry was taken as an example, and a set of index including Gini coefficient, specialization index, industry concentration and industry average concentration ratio index, was introduced to examine the characteristics and mechanism of animal husbandry's geographical agglomeration. The outcomes indicated that, geographical agglomeration of animal husbandry in China has increased constantly during the period from 1980 to 2011. And its evolution feature shows phased change, which is increasing at first and then decreased and then increased steadily. However, the production agglomeration processes of different animal products are very significant. At provincial level, the barycenter of animal husbandry keeps moving northwards, and has gradually formed the differentiation pattern of high concentration in northern China, and that of low concentration in southern China. Factors affecting the geographic agglomeration of the livestock industry mainly include natural resource endowment, agricultural productivity, policies and environment of market operation, of which the mechanism can be explained from the perspective of specialization, economies of scale.
With the declining of traditional industries of agriculture, forestry, fishery and mining, tourism has been one of the significant driving forces in many towns. In the context of rapid development of urbanization and tourism, as an important way to promote the development of urbanization and tourism, a tourism town has become the tourist hotspot and new research focus. In order to explore the current situation and development trend of tourism town research, this paper points out the major results of tourism town research based on the analysis of the related foreign literatures. The paper gives a general review of tourism town research on the major contents, in terms of its evolution, tourism impacts, stakeholders, residents' perception, product development and enterprise behavior, planning and management, and then the research theories and methods are summarized. The conclusions provide a valuable reference for domestic studies. Firstly, the relevant researches abroad are rich range from the groundwork of initial tourism development, economic effects to social, cultural and environmental impacts, stakeholders, marketing and sustainable community development. Cases chosen range from developed counties such as occident to developing counties in Asia and Africa. Secondly, the research of spatial and temporal scales are wide, the capacity and time span of the data are abundant and the regional study scale present binary nature, and a diachronic comparative study of tourism development in the same case at different stages as well as trans-regional contrasts study among different cases are made. Finally, the researches attach great importance to the comprehensive analysis of many theories, quantitative analysis and mode construction and mathematical statistics. Based on the condition of tourism town development and the research status, this article proposes that the following work should be accomplished in the future: completing the study system of tourism town research; analyzing the relationships between various tourism elements and town development; summarizing different paradigms of tourism towns; expanding the space-time scale of tourism research; emphasizing comprehensive analysis of multiple theories and the combination of qualitative and quantitative methods. To strengthen the theoretical and practical research about tourism towns can help assessing the tourism impacts of small towns, analyzing the behavior of stakeholders and predicting the direction of development, which provides a scientific basis for the sustainable development.